This invention relates to packing articles such as jars, bottles and the like in shipping cases or trays such as those made of cardboard or corrugated board, and more particularly to method and apparatus improvements for minimizing damage to fragile articles during such packing.
As disclosed in U.S. Pat. No. 3,869,843, it is known to accumulate articles such as lightweight plastic bottles in end to end relationship in stacks above a loading station and to sequentially release the bottom layer to pockets in a packing grid from whence they are forcibly discharged to a shipping case.
Though such an assembly generally functions well under most conditions, a deficiency exists with thin-walled plastic containers susceptible to damage when roughly handled. More specifically, the stack length (vertical and horizontal components) above the grid loading station can reach to as great as the equivalent of some 200 containers should, for example, the packing system be temporarily shut down while containers continue to be received from the upstream work station. When containers are fed to the stacks under positive pressure, the total pressure on the bottom stack layer, due to such positive pressure plus the dead weight of the stack per se, can approach about 20 pounds or more depending on the relative magnitudes of the pressure components. When the stop at the base of the stack is then removed to charge the packing grid, the base and/or neck portions of the fragile containers frequently fracture when the bottom layer strikes the next lower abutment in the system adjacent containers in prior layers strike each other, thus rendering them unusable. In addition, substantial noise is generated due to the impacting surfaces.